Freeform Optical Design Research Articles

Design and fabrication of a freeform prism array for 3D microscopy

Traditional microscopes have limitations in obtaining true 3D (three-dimensional) stereovision. Although some optical microscopes have been developed for 3D vision, many of them are complex, expensive, or limited to transparent samples. In this research, a freeform optical prism array was designed and fabricated to achieve 3D stereo imaging capability for microscope and machine vision applications. To form clear stereo images from multiple directions simultaneously, freeform optical surface design was applied to the prisms. In a ray tracing operation to determine the optical performance of the freeform prisms, Taylor series was used to calculate the surface shape. The virtual image spot diagrams were generated by using ray tracing methods for both the freeform prisms and the regular prisms. The results showed that all the light rays can be traced back to a single point for the freeform prism, and aberration was much smaller than that of the regular prism. The ray spots formed by the freeform prisms were adequate for image formation. Furthermore, the freeform prism array was fabricated by using a combined ultraprecision diamond turning and slow tool servo broaching process in a single, uninterrupted operation. The slow tool servo process ensured that the relative tolerance among prisms is guaranteed by the precision of the ultraprecision machine without the need for assembly. Finally 3D imaging tests were conducted to verify the freeform prism array's optical performance. The principle of the freeform prism array investigated in this research can be applied to microscopy, machine vision, robotic sensing, and many other areas.

Integrated Manufacturing Technology for Design, Machining and Measurement of Freeform Optics

Ultra-precision machining technology plays an important role in the manufacture of advanced freeform optics. An integrated manufacturing platform is developed to cover freeform optics design,CAD continuous data transform,freeform model re-construction,simulation and cutting optimization of multi-axis machining,compensation of machining errors,and the measurement and characterization of freeform surfaces. The adoption of the platform technology shortens the time to develop complex NC programs for different multi-axis machine tools to manufacture different types of freeform optics. This system helps to avoid expensive repeated cutting tests,as well as to improve the surface quality of freeform products. The stability and effectiveness of the proposed integrated platform are verified through a series of tests.

Design, tolerancing and stray light analyses of a freeform HMD optical system

We are presenting the results of a freeform HMD optical system design. The tolerancing and stray light analyses are carried out to analyze the optical performance of this system. Results are discussed in detail.

Automating design of free-form optics for LED lighting

Automating design of free-form optics for LED lighting